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SW1X MPA I Neptune Push Pull Mono Power Amplifier Monoblock

SW1X Audio Design™ MPA I Neptune

Performance Level 2/3
6V6  Valve Push Pull Mono Power Amplifier


MPA I Neptune is a Pure Class A, Zero Negative Feedback, Fully Valve Rectified, Push Pull, 3 Gain Stage, Mono Power Amplifier.

The powerful & grungy character of the triode connected 6V6G output tubes in combination with 6SJ7 and 6SN7 input and driver tubes offer the articulate presentation with a powerful & full bodied sound.

Combined with the finest Materials & Components, MPA I is refined & musical sounding, especially when combined with higher sensitivity speakers.

(91-93dB/W/1m sensitivty is recommended).

SW1X MPA I Neptune Push Pull Mono Power Amplifier Monoblock

SW1X Audio Design™ MPA I Neptune Mono Power Amplifier Features:

  • Specially Selected and Harmonically Matched Component & Material Quality
  • Push Pull, Zero NFB, Class A, Valve Power Amplifier
  • 6SJ7 input Stage, 6SN7 phase inveter tubes driving the triode connected 6V6 Valves
  • Hybrid Point 2 Point Hardwiring Technique for the most consistent production results
  • Internally wired exclusively with our SW1X Magnum, Genesis and Opus conductors
  • SW1X Audio DesignCustom Designed Copper wound (50 Watt Core) Signal Output Transformers
  • Mono, Directly Heated Double Diode Valve Rectified B+ Power Supply
  • Orient grain M6 EI core mains Transformers & Chokes
  • Fixed Bias Power Supply


Tube Compliment:  2 x 6SJ7, 2 x 6SN7, 4 x 6V6G, 2 x 5U4G


MPA I Neptune is avaiable in 2 Versions with following output transformer (OPTs) specifications:

  • Standard : SW1X Audio Design all Copper wound, orient grain M6 EI Core OPTs
  • Special :  SW1X Audio Designall Copper wound Super HiB DC Core OPTs



Note: Due to SW1X Audio Design’s ongoing research and development process, specifications are subject to change without notice

SW1X MPA I Neptune Push Pull Monoblock Mono Power Amplifier


Push Pull, Class A, Zero NFB, Output Power (W): 9, which sound at least like 90 Watts and the dynamic delivery feel like 600 W

when paired with with High Sensitivity Speakers (93dB/W/1m is recommended)

Input Sensitivity (V): 1

Input Impedance (Ohms): 47K or 100K

Output Impedance (Ohms): 4 & 8

Max Power Consumption (W): 200

Output Noise, Unweighted (mVrms): < 0.5

Dimensions (without tubes and feet): Height (mm) 200 x Width (mm) 250 x Depth (mm) 440

Weight (kg): 40 (pair)

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